Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Polyembryony
Presence of more than one embryo in a seed is termed polyembryony. The phenomenon, first discovered in orange seeds by Leeuwenhoek (1719), attracted considerable attention because of its potential for application in and horticulture. Polyembryony is broadly classified into simple and multiple, depending on whether the supernumerary arises in one or more embryo sacs in the ovule. Simple polyembryony may be sexual or asexual. In sexual polyembryony embryos may originate from the fertilized egg and synergids, or by budding or cleavage of the polyembryony cells or suspensor of the zygotic embryo.
Asexual embryos are produced within the embryo sac without fertilization. Embryos may also originate from diploid nucellar or integumentary cells of the ode and grow into the embryo sac. These embryos are termed adventive or sporophytic. Multiple polyembryonies involve production of accessory embryos from two or more embryo sacs in the same ovule. For example, in the sea Island cotton, Gossypium barbadense, fertilization of egg in one embryo sac stimulates the induction of embryo from an unfertilized egg in the adjacent embryo sac within the same ovule. Thus, diploid-haploid twin embryos are produced in the seed.
Explain the Manifestations of Iron Deficiency Anaemia? • Paleness of conjunctiva • Paleness of tongue • Paleness of mucosa of soft palate • Low haemoglobin • Swelling of
Response to Flooding Prolonged flooding or water-logging creates anaerobic conditions for the sub-surface parts of the plant and synthesis of alcohol dehydrogenase (ADH) helps
What are Tannins? Long known for their inhibitory effects on iron absorption, recent research indicates that tannins do have beneficial effects. Tannins are compounds of high m
Q. Haemodynamics of Tricuspid regurgitation? Right Atrial pressure tracing shows a prominent ‘v' wave and these cannot be appreciated in a patient with atrial fibrillation. RV
Modes of NO - 3 reduction Accordingly, there are the following three basic modes of NO - 3 reduction. Directly dependent upon photosynthesis as in cyanobacter
Altitudinal Variations We know that temperature decreases with increasing altitude. This is mainly due to convection currents in the troposphere - the lowermost (and most dense
What is the function of the collagen fibers of the connective tissue? There are dissimilar collagen types. The major function of these proteins is to keep the shape and the str
HISTORICAL DEVELOPMENT OF PSYCHIATRIC NURSING: History is a record of opportunities, recognized and informed, that produce profound changes in a given field. History of psyc
What is ecotourism, and how can it be used to preserve biodiversity? Ecotourism is tourism involving people who want to see intact ecosystems and their unique organ- isms. Inco
What is the exchange list? IL is a grouping of foods in which specified amounts of all the foods provide approximately equal amount of (the same amount) carbohydrate, protein a
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd